Download Worcester 28Si Technical data

24Si II / 28Si II
WALL MOUNTED COMBINATION BOILERS FOR CENTRAL HEATING
AND MAINS FED DOMESTIC HOT WATER
INSTALLATION AND
SERVICING INSTRUCTIONS
Worcester supports the
Benchmark code of practice
This appliance is for use with Natural Gas or LPG (Cat II 2H3P TYPE C12 & C32)
24Si II GC NUMBER 47 311 65 (N.G.)
GC NUMBER 47 311 66 (L.P.G.)
28Si II GC NUMBER 47 311 67 (N.G.)
GC NUMBER 47 311 68 (L.P.G.)
GB/IE
APPLIANCE OUTPUTS
Domestic
Hot Water
Minimum
Maximum
24Si II 28Si II
6.9 kW 8.1 kW
24 kW 28 kW
Central Heating
24Si II 28Si II
6.9 kW 8.1 kW
24 kW 28 kW
IMPORTANT: THESE INSTRUCTIONS APPLY IN THE GB/IE ONLY
AND MUST BE LEFT WITH THE USER OR AT THE GAS METER
It is IMPORTANT to read the instructions before starting work - they have been
written to make the installation easier and prevent hold-ups.
Contents
1. Installation Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
3. Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
4. Siting the Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
5. Flue Terminal Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
6. Air Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
7. Sealed System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
Open Vent System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
8. Domestic Hot Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
9. Gas Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
.........................................................
10. Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
11. Installing the Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12
12. Commissioning the Appliance . . . . . . . . . . . . . . . . . . . . Page 19
13. Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
14. Inspection and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
15. Replacement of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 24
16. Short Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 30
17. Operational Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . Page 32
18. Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 34
19. Conversion Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . Page 42
1. Installation Regulations
2. Introduction
1.1 Gas Safety (Installation & Use) Regulations 1998:
The appliance is suitable for installation in GB/IE only and
should be installed in accordance with the rules in force.
It is the law in GB that a competent person in accordance with
the above regulations installs all gas appliances.
Failure to install appliances correctly could lead to prosecution.
It is in your interest, and that of safety, to ensure compliance
with the law.
2.1 The
initiative is the new code of practice to encourage
the correct installation, commissioning and servicing of domestic
central heating boilers and system equipment.
The 'checklist' is a vital document that must be completed by
the installer at the time of installation. It confirms that the
boiler has been installed and commissioned according to the
manufacturers instructions.
A declaration of conformity (Refer to IS 813 Annex D1) must be
completed by the installer and a copy supplied to the appliance
operator for boilers installed in Eire.
Without the completion of the checklist and/or declaration,
manufacturers may refuse to respond to a call-out from a
householder, who will be advised that he or she must call back the
installer, who has not fulfilled his obligations to record the
information required by the initiative.
Service:
To ensure continued efficient operation of the appliance it must be
checked at regular intervals. The frequency of servicing will depend
upon the particular installation conditions and usage, but once per
year should generally be adequate. The extent of the service
required by the appliance is determined by the operating condition
of the appliance when tested by fully qualified engineers.
Any service work must be carried out by competent registered
engineers (CORGI in GB).
2.2 General Information
The appliance is set to give the maximum output of 28 kW [28Si II] or
24kW [24Si II] to the domestic hot water and to the heating system.
The hot water flow rate is limited to a nominal 10 l/min [28Si II] or 8
l/min [24Si II] at a maximum temperature rise of 40°C.
The sanitary water section of the appliance is suitable for mains
water pressure of upto 10bar.
Kits are available to convert the appliance from Natural Gas to
Propane operation and vice versa.
2.3 Electrical Supply
230V - 50Hz. Load 180 watts. External fuse 3A (to BS1362),
Internal fuses F1 - 2A, F2 - 1.25A (20mm).
2.4 Gas Supply
The appliances require a maximum of 3.25 m3/h of natural gas
(G20) or 1.25 m3/h of propane (G31) [28Si II] or 2.8 m3/h of
natural gas (G20) or 1.08 m3/h of propane (G31) [24Si II].
The installation and the connection of the gas supply to the
appliance must be in accordance with BS6891.
The meter or regulator should deliver a dynamic pressure of 20 mbar
(G20) or 37mbar (G31) at the appliance, which is equivalent to about
19 mbar or 36 mbar at the gas valve inlet pressure test point.
2.5 Installation
The appliance is suitable for indoor installation only and for use
with a sealed system only.
Do not place anything on top of the appliance.
This is a room sealed appliance and a separate combustion air
supply is not required in any room or compartment in which the
appliance is fitted.
If the appliance is fitted in a cupboard or a compartment is built
around it after installation, then the structure must conform to the
requirements of BS6798 and BS5440 Part 2. However, because of the
low casing losses, there is no need for cooling ventilation openings in
1.2 The manufacturers notes must not be taken, in any way, as
overriding statutory obligations.
1.3 The compliance with a British Standard or European Norm
does not, in itself, confer immunity from legal obligations.
1.4.1 The installation of the appliance must be in accordance
with the relevant requirements of the Gas Safety Regulations,
current IEE Regulations, Building Regulations, Building Standards
(Scotland) and local water by-laws.
1.4.2 In Eire the installation must be carried out by a competent
person and installed in accordance with IS 813, Domestic Gas
Installations (Edition 2), the current building regulations and the
electrical installation must follow the ETCI rules.
1.5 The installation should follow the recommendations of the
following British Standards unless otherwise indicated.
BS5440:1 - Flues and ventilation for gas appliances: Flues
BS5440:2 - Flues and ventilation for gas appliances: Air supply.
BS5449 - Central heating for domestic premises.
BS5482 - Domestic propane gas burning installations.
BS5546:1 - Installation of gas hot water supplies.
BS6700 - Domestic water supply in buildings.
BS6798 - Installation of gas fired hot water boilers.
BS6891- Low pressure gas pipework installations upto 28mm (R1).
BS7593 - Water treatment.
BS7671 - Requirements for electrical installations.
1.6 The appliance does not contain any substances which are
harmful to health.
1.7 In certain circumstances, the installer can be held
responsible, not only for mistakes on his part but also for
damage resulting from the use of faulty materials. We advise
that, to avoid any risk, only quality approved branded fittings
are used.
1.8 LPG Installation:
The appliance shall not be installed in a room or internal space
below ground level when it is intended for use with LPG. This
does not preclude the installation into rooms, which are
basements with respect to one side of the building but open to
the ground on the opposite side.
1.9 These instructions cover, as far as possible, the foreseeable
situations, which may arise.
Contact The Worcester Technical Department, Telephone: 08705
266241, for advice on specific installations.
2
the compartment provided the increased clearances are used.
See Fig. 5.
The spaces specified for servicing must be maintained.(See Table 8).
There is space for the service pipes to pass at the back of the appliance.
2.10 Safety
The appliance must not be operated with the inner casing
cover removed or without being full of water and pressurised.
The gas and electricity supplies must be turned off before
working on the appliance.
Temperature monitoring controls are fitted to prevent overheating.
Automatic frost protection is provided together with automatic
pump seizure protection.
The gas valve solenoids are automatically checked for gas soundness.
IMPORTANT: Where back-flow prevention devices, including
water meters, are fitted the expansion of hot water into cold
water main can be prevented. This can result in a pressure
build-up that may cause damage to the boiler and household
devices such as showers, washing machines etc.
In these cases we recommend that a mini-expansion vessel be
fitted adjacent to the boiler in the cold water supply pipe.
2.11.1 Operation
Central Heating:
A demand for heat will ignite the burner.
It will operate at minimum pressure for 15 seconds before
increasing to the maximum pressure over a period of 1 minute
and then automatically match the system requirements. At the
end of the demand the burner will go out, the pump will
continue to run for upto 4 minutes or the fan for 15 seconds.
There is an anti-cycle time of 3 minutes.
2.11.2 Domestic Hot Water:
A demand for hot water will light the burner. The pressure will
immediately rise to maximum. At the end of the demand the fan
will continue to run for 15 seconds if there is no heating demand.
There is an anti-cycle time of 10 seconds.
2.11.3 Domestic Hot Water and Central Heating Mode.
The demand for hot water will override the CH function when the
appliance is in the heating and hot water mode of operation.
In winter it may be necessary to reduce the flow at the taps to
maintain the delivery temperature.
2.6 Flue
Multi-Directional Horizontal Flue Kit.
Standard Flue Kit can be adjusted from 425mm to
725mm without cutting.
The minimum length is 265 mm with cutting.
Extended flue lengths are available upto a maximum of 4m for
natural gas appliances and 2.5m for LPG.
Optional 45° and 90° flue bend kits are available NOTE: When
using flue bends the maximum flue length is reduced (see
Section 11.12).
If access to the flue terminal will be a problem then a kit is available
to enable the horizontal flue to be fitted from inside the house.
Do not allow the flue terminal to the outside wall to become
obstructed or damaged.
A Tower guard type K2 CG 393553 is available from Tower Flue
Components, Vale Rise, Tonbridge TN9 1TB.
A vertical flue system is available.
2.7 Controls
The appliance has controls for switching the appliance On or Off,
[this does not electrically isolate the appliance] for adjusting the CH
and DHW temperatures. The CH control knob also switches the CH
off and on.
A programmable 'wire free' room thermostat or a facia mounted
programmer or clock is available.
A room thermostat and/or an externally mounted programmer
for mains voltage operation may be connected to the appliance.
Fig. 1. Facia controls
1
2
7
6
3
5
4
Fig. 2. Water flow diagram.
10
9
1.
2.
3.
4.
Mains On/Off control
CH temperature control
DHW temperature control
System pressure gauge
5. Optional programmer
6. Lockout indicator light and
reset button
7. Burner indicator light
2.8 System
8
All dirt must be flushed from the system before
connecting the appliance. The system can be pre-piped and
flushed before the appliance is fitted.
The connections in the system must withstand an operating pressure of
upto 3 bar.
Radiator valves must conform to BS2767: 10:1977.
Table 3 gives the pump head available for the system and the
required temperature differential.
A drain cock must be fitted to the lowest point and an air vent to
the highest point of the system.
7
11
2.9 Showers, Bidets, Taps and Mixing Valves
All taps and mixing valves must be suitable for the available
mains pressure and temperatures upto 65oC.
It may be necessary to fit a pressure reducing valve.
Hot and cold mains fed water can be supplied to overrim bidets
but is subject to local water company requirements.
The flow of water from individual outlets varies on all mains fed
systems that are not fitted with flow balancing valves.
Thermostatically controlled or pressure equalising shower valves
give extra comfort and protection.
If a pressure equalising valve is fitted then the domestic hot
water temperature should be set to maximum.
1
1.
2.
3.
4.
5.
6.
3
2
CH flow
Domestic hot water flow
Domestic hot water supply
CH return
Pressure relife valve discharge
Domestic water flow turbine
6
3
4
5
7. Circulating pump
8. Expansion vessel
9. Primary heat exchanger
10. Automatic air vent
11. By pass
3. Technical Data
Table 1.
24Si II
Table 1.
NOMINAL BOILER RATINGS (10 Minutes After Lighting)
BOILER ADJUSTED FOR G20 (Natural Gas)
BURNER
OUTPUT
INPUT (Net)
GAS RATE
PRESSURE
kW
kW
m bar.
m3/h
6.9
7.9
0.9
0.84
24
26.4
12.1
2.8
6.9
24
28Si II
NOMINAL BOILER RATINGS (10 Minutes After Lighting)
BOILER ADJUSTED FOR G20 (Natural Gas)
BURNER
OUTPUT
INPUT (Net)
GAS RATE
PRESSURE
kW
kW
m bar.
m3/h
8.1
9.2
0.7
0.97
28
30.7
13.1
3.25
BOILER ADJUSTED FOR G31 (Propane)
7.9
3.1
0.32
26.4
35.0
1.08
8.1
28
Natural Gas: Net Input = Gross Input x 0.901
BOILER ADJUSTED FOR G31 (Propane)
9.2
2.8
30.7
34.5
0.38
1.25
LPG (Propane): Net Input = Gross Input x 0.922
NOTE: With longer flue lengths, not using a restrictor, the minimum burner pressure will rise, naturally due to the flue, to 1.1mbar on G20
appliances only.
Table 2.
FLUE DETAILS
HORIZONTAL FLUE
WALL HOLE DIAMETER
STANDARD FLUE
EXTENDED FLUE
mm
110
110
INTERNAL FIX
mm
130
130
MINIMUM LENGTH mm
275/*425
275/*425
MAXIMUM LENGTH mm
725
725
MAXIMUM LENGTH mm
4000
2500
100
100
mm
* NOTE : Minimum uncut length
Table 3
MAXIMUM AVAILABLE PUMP HEAD
HEAD
Metres
MIN. FLOW RATE
L/min.
FLOW/RETURN
DIFFERENTIAL
°C
6.9
5.2
9
11
24
1.8
22
15.5
28
1.8
22
18
Table 4
MECHANICAL SPECIFICATIONS
CENTRAL HEATING FLOW - COMPRESSION
24Si II
22mm
28Si II
22mm
RETURN - COMPRESSION
22mm
22mm
COLD WATER INLET - COMPRESSION
15mm
15mm
DOMESTIC WATER FLOW - COMPRESSION
15mm
15mm
GAS INLET
LPG
EXTERNAL FIX
FLUE ASSEMBLY DIAMETER
BOILER OUTPUT
kW
G20
3
Rp ⁄4
3
Rp ⁄4
RELIEF VALVE DISCHARGE (PUSH-IN)
15mm
15mm
CASING HEIGHT
740mm
740mm
CASING WIDTH
400mm
440mm
CASING DEPTH
360mm
360mm
WEIGHT - LIFT
36kg
36kg
WEIGHT - PACKAGED
48kg
50kg
WEIGHT - DRY
39kg
40kg
4
Table 5
PERFORMANCE SPECIFICATIONS
PRIMARY WATER CAPACITY
24Si II
28Si II
litres
2.0
IP RATING (WHOLE OF BOILER)
IP 20
MAXIMUM MAINS INLET PRESSURE
bar
MINIMUM MAINS INLET PRESSURE (WORKING) FOR MAXIMUM FLOW
bar
1.0
MINIMUM MAINS INLET PRESSURE (WORKING) FOR OPERATION
bar
0.25
DOMESTIC HOT WATER TEMPERATURE RANGE
°C
40 - 60
MAXIMUM CENTRAL HEATING FLOW TEMPERATURE
°C
82 (nom)
MAXIMUM CENTRAL HEATING SYSTEM SET PRESSURE
bar
2.65
MINIMUM CENTRAL HEATING SYSTEM PRESSURE
bar
0.5
OUTPUT TO CENTRAL HEATING & DHW
kw
10
NATURAL GAS (G20)
24
28
LPG - PROPANE (G31)
24
28
DOMESTIC HOT WATER SPECIFIC RATE -
30°C RISE l/min
11.5
13.5
MAXIMUM DOMESTIC HOT WATER FLOW RATE -
40°C RISE l/min
8.5
10
14.9
17.4
FLUE GAS MASS FLOW RATE
FLUE GAS TEMPERATURE °C
146.0
NOx CLASSIFICATION FOR BOTH 24 & 28Si II
Class 3
SEDBUK NUMBER
78.0
78.2
SEDBUK NUMBER LPG
80.5
80
D
D
SEDBUK BAND*
* The value is used in the UK Government Standard Assessment Procedure [SAP] for the energy rating of dwellings. The test data from
which it has been calculated have been certified by the GASTEC notified body.
Table 6
DISCHARGE RATE l/min
TEMPERATURE RISE °C
TEMPERATURE RISE °C
DOMESTIC HOT WATER TEMPERATURE RISE
7
8
24kw
49
43
28kw
57
50
9
38
45
10
34
40
Table 7
GAS SUPPLY SYSTEM - BASED ON NG (G20)
TOTAL LENGTH OF GAS SUPPLY PIPE (COPPER) metres
3
6
9
12
GAS DISCHARGE RATE - PRESSURE DROP mbar. m3/h PIPE DIAMETER mm
8.7
5.8
4.6
3.9
22
18.0
12.0
9.4
8.0
28
Table 8
ABOVE FLUE ELBOW
IN FRONT OF APPLIANCE
BENEATH APPLIANCE
RIGHT AND LEFT HAND SIDE
CLEARANCES
INSTALLATION
30
600
200
10
(mm)
SERVICE
30
600
200
10
Refer to Section 6.
* Front clearance is to a removable panel (eg. door)
Table 9
INITIAL
PRESSURE bar
1.0
1.5
UNVENTILATED COMPARTMENT
150
*240
200
80
SYSTEM CAPACITY
TOTAL SYSTEM VOLUME litres
INITIAL CHARGE PRESSURE bar
0.5
1.0
1.5
57
75
N/A
31
42
52
5
Fig. 6. Side flue opening
Fig. 3. Appliance casing dimensions and
required clearances for installation/servicing
30
150
114
230
24Si II = 400
28Si II = 440
10
10
200
All dimensions in mm
All dimensions in mm
Fig. 4. Appliance casing dimensions and
required clearances (side view).
Fig. 7. Pipework connections
Valves shown closed.
114
230
F
600
A
740
B
C
D
E
View of underside of appliance showing
connections
360
200
All dimensions in mm
20
Fig. 5. Unventilated compartment clearances
A
B
150mm from
the top of the
flue elbow
190
C
D
E
(A, B, C, D,)
F
80mm
80mm
240mm
From a
removable
panel
eg. door
A
B
C
D
E
F
200mm
CH Flow
DHW Flow
Gas
Cold Water Inlet
CH Return
Relief Valve Discharge
=
=
=
=
=
=
24Si II
55
120
185
250
315
375
28Si II
75
140
205
270
335
395
All dimensions in mm
6
4. Siting The Appliance
5. Flue terminal positions
The appliance may be installed in any room but refer to the
requirements of the current IEE Regulations and, in Scotland, the
relevant electrical provisions of the Building Regulations with
respect to the installation of appliances in rooms containing
baths or showers. In Eire refer to the ETCI rules for electrical
installations.
Where a room sealed appliance is installed in a room containing
a bath or shower, any switch or appliance control using mains
electricity must NOT be able to be touched by a person using the
bath or shower. The IP rating of the appliance may only allow it
to be located in specific 'zones'. Refer to, in GB, Electrical
Regulations 16th Edition.
The appliance is NOT suitable for external installation
No special wall protection is required. The wall must be able to
support the weight of the appliance. Refer to Table 4.
The specified clearances must be available for installation and
servicing. Refer to Table 8 and Fig.3, 4.
The appliance can be installed in a cupboard/compartment to
be used for airing clothes providing that the requirements of
BS6798 and BS5440 Part 2 are followed. Refer to Section 2.5.
The airing space must be separated from the boiler space by a
perforated non-combustible partition. Expanded metal or rigid
wire mesh is acceptable provided that the major dimension is
less than 13mm. The clearance between the front of the
appliance and the cupboard or compartment door should be not
less than 75mm.
LPG Installation. Refer to Section 1.8.
The flue system must be installed following the requirements of
BS5440: 1. In Eire the flue termination must be sited as
described in Table 5 of the current edition of IS 813.
Standard horizontal flue kit length is 275 – 725mm with
extension kits for flues upto 4m for natural gas and 2.5m for LPG.
The terminal must not cause an obstruction or the combustion
products a nuisance. Under some conditions the terminal might
steam and positions where this might be a nuisance should be
avoided. Refer to Fig 8.
If the terminal is less than 2m above a surface to which people
have access then a guard must be fitted. The guard must be
evenly spaced about the terminal and fixed with plated screws.
A Type K2 guard is available from Tower Flue Components, Vale
Rise, Tonbridge, TN9 1TB.
Fig. 8. Siting of the flue terminal.
P
Q
Q
D,E.
I
J
N
Q
B
F
M
C
N
N
L
G
TERMINAL POSITION
Aa– Directly below an opening, air brick,
opening windows etc.
B– Above an opening, air brick,
opening windows etc.
C– Horizontally to an opening, air brick,
opening windows etc.
D– Below gutters, soil pipes or drain pipes.
E– Below eaves.
F– Below balconies or car port roof. (Lowest point)
G– From a vertical drain pipe or soil pipe.
H– From an internal or external corner.
I– Above ground, roof or balcony level.
J– From a surface facing the terminal.
K– From a terminal facing the terminal
L– From an opening in a car port (e.g. door
window) into dwelling.
M– Vertically from a terminal on the same
wall.
N– Horizontally from a terminal on the same
wall.
O– From the wall on which the terminal
is mounted
P– From a vertical structure on the roof
Q– Above intersection with roof
A
I
K
H
H
M
MIN. DISTANCE
300 mm
300mm
300mm
75mm
200 mm
200 mm
150 mm
300 mm
300 mm
600 mm
1200 mm
1200 mm
1500 mm
300 mm
N/A
N/A
N/A
Advice should be taken if the terminal is in close proximity to surfaces which may be
of plastic materials ie. car-ports, gutters etc.
NOTE N/A = Not applicable
a
In addition, the terminal should be not nearer than 150mm (fanned draught) to an
opening in the building fabric formed for the purpose of accommodating a built-in element such as a window frame.
7
6. Air Supply
7. Sealed System
6.1 A separate vent for combustion air is not required. Refer to
BS5440:2.
If the appliance is in a cupboard or compartment then, because
of the low casing losses, it is not necessary to have any cooling
ventilation for the boiler. Refer to Section 2.5. There must be
increased clearance around the appliance to allow the free
movement of the air.
Refer to Table 8 and Fig 3, 4 and 5.
The system must comply with requirements of BS6798 and
BS5449 and must not be operated without being full of water
and correctly pressurised. Refer to Fig 8.
The pressure relief valve will operate at 3 bar. The discharge pipe,
of 15mm diameter, must be directed as such that the discharge
of water or steam is visible, will not discharge onto the
occupants of the premises or cause any damage to the premises,
in particular any electrical components or wiring.
The expansion vessel, to BS4814, has a capacity of 8 litres
charged to 0.5 bar, which is suitable for a static head of 5 metres.
A schraeder type valve allows the pressure to be increased if the
static head is greater than 5 metres.
If the expansion vessel fails then it must be replaced with the
designated spare part.
Refer to BS 7074:1, BS5449 and Table 9 for a guide to the
available system capacity. The maximum system design pressure
is 1.5 bar. If the pressure is above 2.65 bar when the appliance is
at maximum temperature then an additional expansion vessel
must be fitted as near to the appliance as possible in the return
pipe. The pressure gauge shows the system pressure.
Fill and pressurise the system through a WRAS approved filling
kit. Refer to Fig. 10 and 11. An optional kit is available. Refer to
Section 16.
The system and the appliance must be fully vented. Repeated
venting loses water from the system, which must be replaced.
The make-up connection must be close to the appliance in the
heating return pipe through an approved non-return valve.
Refer to current building regulations or Good Practice Guide 302
which lists the requirements.
6.2 If the appliance is to be fitted in a cupboard or compartments
with less clearance than the minimum clearances given in Section
4. (Siting The Appliance) then permanent vents for cooling are
required. One at high level and one at low level, either direct to
outside air or to a room. Both vents must pass to the same room
or be on the same wall to the outside air.
6.4 The minimum free areas required are:
24 kW
POSITION OF
AIR VENTS
AIR FROM
THE ROOM
AIR DIRECT
FROM OUTSIDE
HIGH LEVEL
264cm
LOW LEVEL
264cm
132cm
POSITION OF
AIR VENTS
AIR FROM
THE ROOM
AIR DIRECT
FROM OUTSIDE
HIGH LEVEL
307cm
2
2
132cm
2
2
28 kW
LOW LEVEL
2
Plastic Pipes
2
154cm
2
Plastic pipes must not be directly connected to the boiler. A
copper to plastic transition piece should be positioned a
minimum of 600mm from the boiler. A plastic pipe with a
polymeric barrier should be used.
The connection to the mains water supply must have the
approval of the local Water Company.
The pump is set at maximum and should not be adjusted.
All connections in the system must withstand a working pressure of up
to 3 bar.
The radiator valves must conform to BS 2767:10 and other
valves to BS1010.
2
307cm
154cm
Open Vent System
This appliance is NOT suitable for connection to an open vent
system.
Fig. 9. Sealed primary water system.
APPLIANCE
Mains cold
water
Refer to
'Water Flow
Diagram'
Fig.2.
Radiator
valve
Hot water out
Lockshield
valve
Heating
return
Heating
flow
NOTE: A drain cock should be installed at the
lowest point of the heating circuit and below the
level of the appliance.
Cold water inlet
British Standard stop valve.
Fixed spindle type
Water main
8
Fig 10 - System Fill
Fig 11 - System make up
4
2
Mains water
supply
Heating
return
Hose union
1
300mm Above
the highest point
of the system
3
Non return Non return
valve
valve
5
6
1.Central Heating Return
2.Auto Air vent
3.Non-return Valve
4.Make-up Vessel
5.Stop Cock
6.Fill Point
Stop
cock
Temporary hose
Test cock
8. Domestic Hot Water
9. Gas Supply
It may be necessary to contact the local Water Company before
connecting the appliance. Where back-flow prevention devices,
including water meters, are fitted the expansion of hot water into
cold water main can be prevented. This can result in a pressure
build-up that may cause damage to the boiler and household
devices such as showers, washing machines etc.
In these cases we recommend that a mini-expansion vessel be
fitted adjacent to the boiler in the cold water pipe.
The last 600mm of mains water pipe before the appliance must
be in copper.
The domestic hot water circuit of the appliance is suitable for a
mains pressure of upto 10bar. A pressure reducing valve must be
fitted if necessary.
A mains water supply isolating valve is fitted.
The maximum hot water flow rate is set at the factory to 8 l/min
[24Si II] and 10 l/min [28Si II] giving a nominal temperature rise
of 40oC with the temperature control at maximum. This rate is
equivalent to a Specific Rate of 11.5 l/min [24Si II] and 12.9
l/min [28Si II] at a rise of 30oC. Refer to Table 6. The temperature
rise, upto the maximum set by the user, is maintained by the
automatic modulation of the heat input.
In winter, when the water temperature is lower it may be
necessary to reduce the water flow at the tap or shower to
maintain the maximum delivery temperature.
It is recommended that long pipe runs to taps or showers are
insulated to prevent the rapid cooling of the water.
Hot and cold taps and mixing valves must be suitable for the
available mains pressure.
No anti-syphonage arrangements are necessary for fixed head
showers. The hose of a loose-head shower must be fixed so that
the shower head cannot get closer than 25mm to the top edge of
the bath to prevent its immersion in the water. Alternatively the
shower can be fitted with an anti-syphonage device at the flexible
hose connection. Thermostatically controlled or pressure
balancing shower valves will give extra comfort and guard
against extreme temperature.
Hot and cold mains water direct to a bidet is, subject to the
approval of the local water company, permissible provided that
the bidet is of the overrim flushing type. The outlets must be
shrouded and unable to be fitted with a hand-held spray. No antisyphon arrangements are needed.
LIME SCALE: In areas of temporary hardness [>200ppm of calcium
carbonate] it is suggested that a proprietary scale reducer is fitted
in the mains cold water connection to the appliance. Installation of
a scale inhibitor assembly must be in accordance with the
requirements of the local Water Company. The water hardness can
be determined by reference to the local Water Company.
An isolating valve should be fitted to allow servicing.
The appliance requires a maximum of 2.8 m 3/h [24Si II],
3.25m3/h [28Si II] of natural gas (G20) or 1.08 m3/h [24Si II],
1.25m3/h [28Si II] of propane (G31). Refer to Table 7.
A natural gas appliance must be connected to a governed meter.
The installation and connection of the gas supply to the
appliance must be in accordance with BS6891.
The meter (NG) or regulator (LPG) and the pipework to the
appliance must be checked, preferably by the gas supplier, to
ensure that a dynamic pressure of 20mbar for natural gas or
37mbar for propane is available at the appliance (contact gas
supplier if in doubt) equivalent to about 19mbar [NG] or 36mbar
[LPG] respectively at the gas valve inlet pressure connection and
that the gas flow is adequate for all the installed gas appliances
operating together.
10. Electrical
Mains supply: 230V ~ 50 Hz 180watts.
External fuse 3A to BS1362. Internal fuses F1-T2A, F2-TI.25A
(20mm). Spare internal fuses are supplied with the appliance.
The mains cable must be 0.75mm2 (24x0.20 mm) to BS6500 Table 16 and must be connected to the terminal ST2 marked L
(red or brown lead), N (black or blue lead) and the Earth stud
(green or green/yellow lead) and secured with the cable clamp.
The Earth lead must still be slack when the other leads are taut.
Refer to Fig 14 and 15.
The appliance must be earthed.
The wiring between the appliance and the electrical supply shall
comply with current IEE wiring regulations (and any local regulations
which apply) for fixed wiring to a stationary appliance.
NB. It must be possible to completely isolate the appliance with at
least 3mm contact separation in both poles.
A room thermostat or externally mounted programmer must be
suitable for mains voltage operation. The leads must be securely fixed
in the cable clamps (see Fig. 35)
A facia mounted digital programmer or mechanical timer or receiver
for wireless programmable room thermostat is available as an
optional extra. Instructions are supplied with the product.
On very rare occasions it may be necessary to fit an external
frost thermostat to protect remote parts of the system. In this
case refer to the WHS Technical Department for information,
Tel: 08705 266241.
9
Fig. 12. Wiring diagram.
Air
Pressure
Switch
Fan
small tab=L high speed (red)
medium tab = L low speed (white)
large tab=N (black)
blue
k
blac
Overheat cut-off
device
black
CH sensor
(front of heat
exchanger)
red
Flame sense
electrode
Spark
electrode
Gas valve
Regulator
valve
Flow
turbine
DHW sensor
Pump
Safety
valve
Safety
valve
Control Board
Earth tabs
Spark
Generator
ST5
Code Plug
green/yellow
green
white
black
2 green
red
white
black
blue
brown
Link
Mains in
ST16
ST1
ST15
blue
brown
ST2
yellow
black
blue
2 blue
2 brown
black
red
green
2 green
10
LIVE
IN
ST2 Pin N
ST2 Pin L
On/Off
switch
11
ST15
right
pin
ST2
(LS)
red
Electronics
Electronics
N
Convert AC to low
voltage electronics
low high
ST1
right
pin
ST2
(LR)
Spark
Indicators
Settings
Electronics/
microprocessor
(Safety Low Voltage)
white
ST1
centre
pin
Optional link
Room
thermostat
ST2
(NS)
Transformer
Fuse F2
(1.25A Slow)
Red
Red
Flame detect
Error
indicator indicator/reset
Outputs
(Ls)
(for other features)
ST2
centre pole
Fuse F1
(2A Slow)
N
Spark
electrodes
24V programmer (if applicable)
Overheat cut-off
Flame sense
Air pressure switch
DHW sensor
CH sensor
Flow sensor
Main valve
Regulator valve
Fig. 13. Functional flow diagram.
Inputs
DHW control knob
CH Control knob
Gas valve mode switch
Reset button
Electronics
Fan
Pump
Fig. 14. Access to internal fuses and
electrical connections.
Fig. 15 . Mains electricity connections.
1
3
2
N Ns Ls Ns
L
230V
Ls
MAINS
LR
230V
4
1. Connection cover fixing screws
2. Connection cover
3. Control panel
4. Connections
11.6 Gas and Water Pipes
Remove the gas cock and fix the appropriate fitting to connect
the inlet pipe and refit. Refer Fig 17.
If it is necessary for any of the pipes to run up the back of the
appliance then they must be arranged to pass behind the
expansion vessel. Refer to Fig 3. Pipework must not run
horizontally within the limits of the casing.
It is important that the pipes are not fixed near the appliance
using clips that put a strain on the connections.
11. Installing The Appliance
NOTE: READ THIS SECTION FULLY BEFORE COMMENCING THE
INSTALLATION.
11.1 General
The appliance is only suitable for fitting to a sealed system.
The flue must be installed as specified in BS5440:1 and the
current Building Regulations.
Before the appliance is fitted to the wall thoroughly
flush the system and mains water supply.
11.2 Unpacking
Remove the appliance from its packaging and check the contents
against the packing list.
Unscrew the service connections and remove the wall mounting
assembly.
NOTE: The wall mounting assembly can be removed from the
carton without having to remove the boiler.
Fig. 16. Wall mounting assembly
338
11.3 Site Preparation
Check that the correct position for the appliance has been
chosen. Refer to Section 4 and Table 8.
Check that the wall is flat and will support the weight of the
appliance. Refer to Table 4.
65
60
60
11.4 Fixing Holes and Flue Opening
Hold the wall mounting assembly or template against the wall.
Check that the assembly or template is level. Mark the position
of the fixing holes and the flue opening. Refer to Fig 16.
The diamond cut-out indicates the centreline of the appliance.
Mark the centrelines of the pipe connections to aid the preplumbing of the system pipework.
Pre-plumbing is not recommended if no movement in the pipes
is available.
Check the position of the fixing points and flue opening before
drilling the fixing holes 60mm deep for the No. 12 size plugs and
cutting the flue duct hole at 110mm diameter [150mm diameter
for internally fitted flues].
367
740
480
75
218
11.5 Wall Mounting and Manifold Assembly
Fit the plugs and insert the bottom screws.
Check that all service valves are closed.
Offer the assembly to the wall utilising the keyhole slots on the
manifold assembly and fix to the wall. Refer to Fig 16 and 17.
Check that the assembly is properly aligned before tightening
the screws.
12
20
All dimensions in mm
Fig. 19 . Wall mounting frame
Fig. 17 . Manifold assembly
3
Wall
Frame
Wall
Frame
Fibre
Washer
65
CH
Flow
65
65
2
4
1
65
1. Wall mounting frame
2. Hanging bracket
3. Appliance
4. Support hook
DHW
Flow
Gas
DHW
Cold
Inlet
CH
Return
Lift the appliance to the wall, engage in the top support and
lower onto the manifold assembly. Tighten the gas and water
connections.
Fit a discharge pipe to the relief valve leading it away from any
electrics or where it might be a hazard. Lower the facia to gain
access. The pipe must not be less than 15mm in diameter and
must run continuously downward outside the appliance. Refer to
Fig 20.
All dimensions in mm
Fig. 18 . Facia cover
Fig. 20 . Relief valve drain connection
1
1
2
2
3
4
3
5
1. Appliance
2. Controls
3. Facia cover
4. Facia cover clips (4)
4
1. Pump
2. Boiler drain
3. Pressure gauge capillary
4. Relief valve
5. Relief valve drain connection (push fit)
11.7 Install the Boiler
Pull off the clip on facia cover and remove the cabinet by
unscrewing the two fixing screws, releasing the sides and lifting
from the top location.
Check that the gas and water valves are closed. Refer to Fig 17.
Fit the new seals, in the hardware pack, to the service valves on
the manifold.
13
Fig. 21. Inner case and facia fixing
Fig. 22. Flue spigot and restrictor
1
3
2
3
1
1.
2.
3.
4.
Flue spigot fixing screws
Flue spigot
Restrictor ring
Flue spigot fixing holes
4
Fig.23. Standard flue assembly
4
Terminal
assembly
L
5
Flue
turret
assembly
10
9
7
2
Fixing screw
8
6
2
Telescopic adjustment
Appliance
casing
7
11
Fit the flue restrictor ring by unscrewing the flue spigot from the
boiler. Refer to Fig. 22.
The standard telescopic flue assembly is suitable (without
cutting) for flues from 425mm up to 725mm measured from the
centre-line of the boiler flue outlet to the outer face of the wall.
Refer to Fig.23.
The minimum length of the standard flue, after cutting is 275mm.
If L is greater than 725mm then extension duct kit/s will be required
- each kit extends the flue by 750mm up to a maximum of 4000
mm for natural gas boilers and 2500mm for LPG. See table below.
1. Inner casing cover
2. Cabinet fixing screws (4)
3. Inner casing cover fixing screws (2)
4. Inner casing cover fixing screws (2)
5. Facia control panel
6. Controls connector cover
7. Controls connector cover fixing screws (2)
8. Programmer (optional)
9. Facia control panel fixing screw
10. Top support lug (2)
11. Bottom support lug (2)
EXTENSION
1
2
3
4
5
11.8 Air and Flue Duct Preparation
The method of installation of the flue system may be varied to
suit the actual site conditions. The instructions for connecting
and fixing the ducts must, however, be strictly followed.
11.9 Measure and Cut the Ducts.
General: Cut the ducts as necessary, ensuring that the cuts are
square and free from burrs. Always check the dimensions before
cutting.
Measure the distance L. Refer to Fig. 23, 24, 25 and 26.
Remove all packing material from the flue components.
The standard flue can be telescopically adjusted to any length
between 425mm and 725mm measured from the centre of the
turret without the need to cut the ducts.
Fix the flue assembly together using the self-tapping screws
provided. Refer to Fig. 23.
RESTRICTOR RINGS
Flue length
Horizontal up to 725mm
Horizontal above 725mm
LPG Horizontal up to 725mm
Vertical terminal length only 1200mm
Vertical flue greater than 1200mm
24Si II
76mm
None
76mm
78mm
None
MAXIMUM FLUE LENGTH mm
1475
2225
2975
3725
4000
28Si II
78mm
None
77mm
82mm
None
It will only be necessary to cut the standard assembly if L is less
than 425mm. Cut the flue turret assembly and the terminal
assembly by the same amount eg. if L=350 – remove 75mm
(425-350) from each assembly.
14
Fig. 24. Extension duct
Terminal
assembly
L
Flue
turret
assembly
Fixing screw
Appliance
Fixing screw
casing
Ducts of equal length
Fig. 25. Flue duct length - side
Terminal
assembly
L
Flue
turret
assembly
It will be necessary to cut the ducts
Fig. 26. Flue duct length - rear
If L is between
Flue
turret
assembly
Terminal
assembly
L
725 - 1175mm
1475 - 1925mm
*2225 - 2675mm
2975 - 3425mm
3725 - 4000mm
(1 extension)
(2 extension)
(3 extension)
(4 extension)
(5 extension)
(* Maximum length 2500mm for LPG boilers)
It is necessary to shorten the assembly by cutting the first
extension duct assembly eg. L = 1000mm - remove 175mm
from the air and flue ducts (1175 – 1000 = 175mm).
NOTE: Extension duct measurements do not include the
socketed end. Unless specifically instructed the socketed end
must not be removed.
Fix the flue ducts together before fixing the surrounding air duct,
the cut ducts fit into the terminal assembly.
11.10 Fitting the Flue Assembly with Access to the Terminal.
Prepare the flue duct assembly as described in Section 11.8.
Apply the plastic tape to the air duct to be in contact with the
external brickwork.
From inside push the assembly through the wall. Align the flue
turret and push fully onto the spigot on the appliance. Tighten
the clamping ring. Refer to Fig.27.
It is not necessary to cut the ducts
If L is between
1175 - 1475mm
1925 - 2225mm
*2675 - 2975mm
3425 - 3725mm
(1 extension)
(2 extension)
(3 extension)
(4 extension)
Make good the internal wall face and the external brickwork or
rendering.
11.11 Fitting of the Flue Assembly without access to the Terminal.
The rubber gasket kit is available as a spare part.
NOTE: A larger diameter opening in the wall is required. Refer to
Table 2.
(* Maximum length 2500mm for LPG boilers)
15
Prepare the flue assembly as described in Section 11.8.
Fig. 27 . Flue Turret Fixing
Fit the rubber sealing gasket centrally onto the terminal
assembly and tighten the clamp. Refer to Fig. 28.
Apply the plastic tape to the air duct to be in contact with the
external brickwork.
1
From inside push the assembly through the wall so that the
gasket flange is against the outer face. Refer to Fig. 28.
It may be necessary to adjust the legs of the flue centering ring.
Align the flue turret and push fully onto the socket on the
appliance. Tighten the clamping ring. Refer to Fig 27.
Seal the gap around the duct at the inner wall face with the
flexible seal provided and make good.
2
3
11.12 Flue Bends.
90° and 45° bends are available. A maximum of two bends may
be used in addition to the first bend on the flue turret.
A 90° bend is equivalent to 750mm of straight duct.
A 45° bend is equivalent to 375mm of straight duct.
1. Flue turret assembly
2. Clamp
3. Appliance
A maximum flue assembly of 3250mm for natural gas and
1750mm for LPG is possible with 1 X 90° bend and 2500mm
natural gas and 1000mm for LPG with 2 X 90° bends.
Measure the lengths X,Y and Z. Refer to Fig.29.
The maximum value of X using the turret assembly only is 506mm.
Reduce the ducts to the appropriate length eg. X = 406mm, cut
100mm from the air duct and 120mm (to cover the entry into the
45° or 90° elbow) from the flue duct. Refer to Fig.30.
Fig. 28 . Terminal assembly for internal
fitting of the flue.
Flue centering ring
Air duct
Flue duct
Fixing clamp
Flue Terminal
NOTE: The flue system ducts between the elbows, dimension Y,
requires the socketed ends (of the first extension if two or more
are used) to be removed and the air and flue tubes to be cut to
the same length.
Cut the ducts to a length Y – 162mm. Refer to Fig.29.
The final section, dimension Z, of the flue system must include a
section of plain duct assembly eg. an extension assembly with
the sockets removed. Reduce the final section, including the
terminal assembly, by the appropriate amount eg:
Air duct Z - 81mm and the flue duct Z – 51mm. Refer to Fig.29.
Rubber sealing gasket
If Z is less than 425mm it will be necessary to cut the air and flue
ducts of the extension to a plain length of 100mm and reduce
the length of the terminal assembly eg. Z=350mm - remove
75mm from the terminal assembly.
Rubber sealing
gasket
Flue terminal
If Z is between 425 - 725mm it is not necessary to cut the
terminal assembly or use a second extension duct as the length
can be set telescopically.
Clamping ring
Z
Fig. 29. Flue bends
Y-162
Plain tube
Y
X
16
If Z is greater than 725mm then two extension duct assemblies will
be required, the first assembly being cut to length as plain tubes.
Connect the mains supply lead to the appliance and secure in
the cable clamp. Make sure that the lead is isolated before
connection. Refer to Section 10.
Check that there is sufficient loose lead to allow the release of the
facia panel assembly and that the earth lead of the mains supply
is longer than the live and neutral leads.
Fit the facia-mounted clock or programmer. Full instructions are
sent with the control. Refer to Fig 33 and 34.
Connect any external controls ensuring that the leads pass
through the appropriate cable clamp. Refer to Section 10 and Fig
35 and 36.
Test for gas soundness as described in BS6891.
If the appliance is not to be commissioned immediately, replace
the connection cover panel and the cabinet.
Check that the gas and electricity services have been turned off.
If more than two extension ducts are needed in any section to
achieve the required length then the final section of the
assembly must not be less than 275mm without cutting the
terminal assembly.
NOTE: The flue duct of the final extension must be 30mm longer
than the air duct.
Each section must be connected to the previous section of the
flue bend by fixing the flue ducts together and then similarly
fixing the air ducts which engage the elbows.
Fit the assembly as described in Section 11.9, 11.10 as
appropriate.
Make good the internal and external brickwork or rendering.
Fig. 32. Facia connections cover
11.13 Vertical Adapter for Horizontal Flues
An adapter is available for an initial short section of vertical flue.
Refer to Fig. 31.
Measure and cut the flue as described in Section 11.11.
The first, vertical, section (equivalent to dimension X) is
measured from the top of the boiler casing. Cut the vertical
section of the extension duct to 167mm less than the measured
distance. Do not remove the socketed ends.
The minimum measured distance is 167mm.
Seal the air duct to the spigot using silicone sealant.
2
2
1
11.14 Completion of the Installation
Check that all the gas and water connections on the manifold
have been tightened.
Undo the two screws and remove the connections cover panel.
Refer to Fig 32.
Fig. 30 - Elbow to Flue Turret
Assembly.
1. Controls connector cover
2. Controls connector cover fixing screws (2)
120mm
Fig. 33. Programmer connection
7
6
100mm
*5mm
Flue Turret
5
Bend
4
*When connecting to an elbow the flue duct must be
5mm longer than the air duct.
3
Fig. 31 Vertical Adapter.
2
Flue Duct
Air Duct
1
1.
2.
3.
4.
5.
6.
7.
Adapter
Flue Spigot
17
Facia (gently pull forward to un-clip and remove)
Control panel (boiler outer casing in place)
Programmer cover (un-clip to remove. See Fig. 34)
Programmer location in detail
Programmer connections (See Fig. 34)
Programmer connector plug
Programmer
Fig 36 - Mains Voltage External Controls
Connections
Fig. 34. Programmer cover
3
N Ns Ls Ns Ls LR spare
L
N Ns Ls Ns Ls LR spare
L
Remove Link
Live
Switched Live
ST2
Neutral
Live
Neutral
1
Switched Live
ST2
Remove Link
Motor
230 V Room Thermostat Connections
2
230 V Programmer Connections
230 V room thermostat and
Programmer Connections
1. Programmer connections
2. Boiler outer casing
3. Cover panel
N Ns Ls Ns Ls LR spare
L
Live
ive
dL
he
itc
Sw
Ne
ut
ral
e
Liv
Remove Link
Neutral
ST2
Motor
Fig. 35. Facia connections
2
2
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Controls connector cover
Controls connector cover fixing screws (2)
Facia control panel
Earth connection (tags)
Earth connection (screws)
Cable clamp
Fuse F1 2A (slow)
Cable clamp
ST15 Pump
ST1 Fan
Fuse F2 1.25A (slow)
Code plug
Commissioning switch
(gas valve mode switch)
14. Internal controls connectors
15. Mains and external controls connectors
(230 Volt)
1
3
4
5
15
ST2
6
Series
connection
point
7
9
8
10
11 12 13
8
18
14
Fig. 38. Pump venting.
12. Commissioning The Appliance
Water Treatment: For optimum performance after
installation, this boiler and its associated central heating system
should be flushed in accordance with the guidelines given in
BS7593: 1992 – Treatment of water in domestic hot water heating
systems. Full instructions are supplied with proprietary cleansers
sold for this purpose. If an inhibitor is to be used after flushing, it
should be used in accordance with the manufacturers instructions.
Remove all system cleanser before adding any inhibitor.
Suitable flushing agents and inhibitors are available from Betz
Dearborn on 0151 4209563 or Fernox on 01799 550811.
Pump
Pump cap
Electrical
connections
cover
12.1 System Set up
Remove the cabinet by pulling off the clip-on facia cover.
Unscrew the two fixing screws, release the sides and lift from the
top location.
Check that the electrical supply and the gas supply to the
appliance are turned off and that all the water connections
throughout the system are tight.
Open the system valves at the appliance. Refer to Fig 17.
Open all the radiator valves. Remove the automatic air vent cap.
Refer to Fig 37.
expansion vessel to allow the charge pressure to be increased if
necessary. Refer to Fig 37.
The expansion vessel must be charged to 0.35bar less than the
initial system design pressure.
Note: 1bar = 10.2m of water.
12.3 Set the System Pressure
Fill the system until the pressure gauge is at 2.5bar and check for
leaks. Release water from the system using the relief valve test
knob until the required system pressure is obtained, upto a
maximum of 1.5bar. Set the pointer on the pressure gauge to
record the set system pressure.
If the pressure indicated on the gauge is greater than 2.65bar
when operating at the maximum central heating temperature
then an extra expansion vessel must be fitted to the system as
close as possible to the appliance central heating return
connection.
Fig. 37. Automatic air vent and combustion
test point
Flue connections
Automatic air vent
Expansion vessel charging point
12.4 Clock/Programmer
The controls fitted to the appliance should be set up at this
stage. Refer to the instructions sent with the control.
Expansion vessel
12.5 Checking the Burner Pressure
Check that the gas and electricity supplies are turned off.
Connect pressure gauges to the gas valve to measure the inlet
and burner pressures. Refer to Fig 39.
The appliance is fully set up in the factory and no adjustment
should be necessary.
Combustion products
test point (front cap)
Wall mounting frame
Fig. 39. Gas valve.
Fill the system through an external WRAS approved filling loop
or Worcester Filling Link and Key optional extra, Part No: 7 716
192 281. Refer to Section 7, Sealed System.
Vent each radiator in turn. The automatic air vent, cap removed,
will vent the appliance. Refer to Fig 37.
It is very imortant that the appliance and system are fully vented
and that all air pockets are removed.
Remove the cap from the pump and turn the shaft about half a
turn. Replace the cap. Refer to Fig 38.
Burner
pressure
test point
Check that the pressure relief valve operates by turning the knob
anti-clockwise until it releases. Lower the facia to gain access to
the relief valve. Refer to Fig 20. Water should be expelled from
the discharge pipe. Refer also to Fig 54.
The appliance [as despatched] can accommodate a system volume
of 100 litres. Refer to BS7074 Part 1, BS5449 and Table 8. If the
system volume is greater then an extra vessel must be fitted as
close as possible to the appliance central heating return connection
and pressurised to the same figure as the integral vessel.
Main gas
valve
connections
12.2 Set the Expansion Vessel Pressure
The charge pressure of the expansion vessel as dispatched is
0.5bar, which is equivalent to a static head of 5m. The charge
pressure must not be less than the static head at the point of
connection. A Schraeder type valve is fitted to the
Inlet
pressure
test point
19
Max
2mm
Allen key
Min
3mm
Allen key
Minimum /
Maximum
pressure
adjuster Allen key*
(see Note)
Gas valve
Electrical
sealing
connections
cap
modulator
(Blue:Blue)
*Note: Clockwise
to increase and
anti-clockwise to
decrease the pressure.
Unscrew and remove the control connector cover to display the
mode switch. Refer to Fig 32.
Check that all the radiator valves are open. Check that the
system is fully vented, pressurised and set to the required
pressure as indicated on the gauge.
Set the temperature control knobs to maximum and the
clock/programmer to operate continuously.
Fully open a hot tap.
12.7 Central Heating
Check that all the radiator valves are open.
Check that the system is fully vented, pressurised and set to the
required pressure as indicated on the gauge.
Check that the clock/programmer is set to operate continuously.
Set the room thermostat and the central heating temperature
control to maximum.
The burner will light and the appliance will modulate its output
from minimum to maximum over a period of about two minutes.
Check that all the radiators are heating up evenly. Shut down all
but one of the radiators and observe the burner pressure fall.
Open all the radiators and check that the burner pressure rises.
Fig.40. Mode adjustment
Balance the system to give the required temperature differential.
Refer to Table 3.
Betrieb
Max
Set the room thermostat to minimum and check that the burner
goes out.
Reset the room thermostat to maximum and the burner will relight and follow the normal operating procedure.
S4
Min
12.8 Check flame failure device
Turn off the gas service cock. The burner will go out but sparking
from the electrode will continue for 10 seconds when the
appliance will ‘lock-out’. After 60 seconds carefully open the gas
service cock, press the reset button and observe the burner relight and follow the normal sequence of operation. Refer to Fig
17 and 41.
Turn off the gas service cock and the electricity supply to the
appliance.
Drain the system while the appliance is hot.
Refill, vent and re-pressurise the system as described in Section
12.1 preceding, adding, if necessary, a suitable proprietary
inhibitor.
Further information is available from Betz Dearborn on 0151
4209563 or Fernox on 01799 550811.
Set the mode switch to MAX. Refer to Fig 40.
Turn on the gas and electricity supplies.
A continuous spark will occur until the burner is alight and
sensed by the control circuit. The burner will remain at its
maximum domestic hot water pressure for 1 minute. Refer to
Table 1. It should not be necessary for the gas valve to be
adjusted.
Note: The burner pressure is factory set and if, after checking that
the dynamic (working) supply pressure is sufficient i.e. 19.0mb
approx. [NG] or 36mbar approx. [LPG] at the gas valve inlet
pressure test point, the correct pressure cannot be obtained then
The Worcester Service Department should be contacted.
If the appliance does not light then check that it is not in the
‘lock-out’ state by gently pressing the reset button for 5 seconds.
Refer to Fig 41.
Set the mode switch to Normal.
Turn off the hot tap.
The burner pressure will drop to the minimum setting and will
ramp up to the maximum central heating pressure appropriate
to the appliance and the gas. Refer to Table 1.
Set the mode switch to MIN.
The burner pressure will drop to the minimum burner pressure
appropriate to the appliance and the gas for both the central
heating and domestic hot water modes. Refer to Table 1.
Test for gas soundness at the joint between the burner and the
gas valve with leak detection fluid.
Set the mode switch back to Normal.
Turn the electricity supply off and then back on to reset the
controls.
Replace the controls connector panel.
12.9 Domestic Hot Water and Central Heating
Set all controls to maximum. Turn on the electricity supply to the
appliance and open the gas service cock at the appliance. The
burner will light and heat will pass into the system.
Turn on a hot tap and check that hot water is soon discharged
from the tap. Close the tap and the burner will go off. The
appliance will then return to the central heating mode and
automatically balance with the system requirements.
12.10 Completion of Commissioning
Turn off the appliance and disconnect the pressure gauge and
tighten the test point screw.
Restart the appliance and check for gas soundness around the
test point screw.
Refit the cabinet.
If the appliance is to be passed over to the user immediately
then set the controls to the users requirements.
If the appliance is to be left inoperative in frosty conditions then
set the programmer, if fitted, to off. Do not turn the electricity or
gas supplies off. The appliance will operate under the control of
the integral frost protection facility.
If there is any possibility of the appliance being left totally
unused in freezing conditions then switch off the gas and
electricity and drain the appliance and the system.
The appliance must be fully re-commissioned when it is returned
to service. The venting of the appliance is very important.
12.6 Operation of the appliance
Domestic Hot Water
Turn the central heating temperature control knob fully anticlockwise.
Open a hot tap near the appliance. The burner will light and go to
the maximum burner pressure appropriate to the appliance and
the gas. Refer to Table 1. Gradually close the tap and check that
the burner pressure falls. Fully open the tap and check that the
pressure rises. Close the tap and check that the burner goes out.
The fan and pump may continue running until the appliance has
cooled to a pre-set temperature.
20
13. Handover
Fig. 42. Inner case and facia fixing
3
1
Fig. 41. Facia controls
7
6
5
12
1
1.
2.
3.
4.
2
Mains On/Off control
CH temperature control
DHW temperature control
System pressure gauge
3
4
4
5. Optional programmer
6. Lockout indicator lamp and
reset button
7. Burner indicator lamp
5
7
2
6
Hand over the User Booklet and the completed
Benchmark Checklist.
Explain how to operate the appliance safely and efficiently.
Tell the user what to do if the appliance is not to be used in very
cold conditions.
Tell the user what to do if the system pressure falls.
Explain that regular servicing will maintain the safe and efficient
operation and extend the life of the appliance. WHS or their
agent can offer a comprehensive maintenance contract.
Tell the user that any work on the appliance must only be
carried-out by a competent, registered, person (CORGI in GB).
10
9
8
2
7
11
1. Inner casing cover
2. Cabinet fixing screws (4)
3. Inner casing cover fixing screws (2)
4. Inner casing cover fixing screws (2)
5. Facia control panel
6. Controls connector cover
7. Controls connector cover fixing screws (2)
8. Programmer (optional)
9. Facia control panel fixing screw
10. Top support lug (2)
11. Bottom support lug (2)
12. Sight glass
14. Inspection And Service
14.1
To ensure continued efficient operation of the appliance it must be
checked at regular intervals. The frequency of servicing will depend
upon the particular installation conditions and usage, but once per
year should generally be adequate. The extent of the service
required by the appliance is determined by the operating condition
of the appliance when tested by fully qualified engineers.
Any service work must be carried out by competent registered
engineers (CORGI in GB).
14.2 Inspection
Check that the terminal and the terminal guard, if fitted, are clear
and undamaged.
If the appliance is in a compartment or cupboard check that the
specified service space around the appliance is clear. Refer to Table 8.
Check all the joints and connections in the system and remake
any that show signs of leakage. Refill and re-pressurise as
described in Section 12-Commissioning.
Operate the appliance and take note of any irregularities. Refer to
Section 18-Fault Finding for rectification procedures.
If the combustion performance is to be checked:
Remove the cap from the sample point on the top of the
appliance. Refer to Fig 37.
Connect an approved sampling meter.
With the appliance at maximum rate and stable in the DHW
mode expect readings of:
Fig. 43. Facia in service position
gas supply at the gas service cock on the appliance before
starting any service procedures.
Always test for gas soundness after the service has been
completed.
14.3 Component Access
To service the appliance it may be necessary to remove some or
all of the following parts to gain access to components which
may need to be checked or replaced.
Cabinet
Pull off the clip-on facia cover. Unscrew the two
screws and release the sides. Lift up and away from
the top locating pegs.
Facia Panel Unscrew the single screw, lift off and lower onto the
lower support lugs. Refer to Fig 42 & 43.
24kW NG CO2 5.3—6.2% CO 0.002—0.010%
LPG CO2 6.4—7.4% CO 0.004—0.010%
28kW NG CO2 5.6—6.4% CO 0.006—0.010%
LPG CO2 6.3—7.3% CO 0.003—0.010%
NB For flues greater than 725mm without a restrictor the CO2
may be up to 0.5% lower.
These figures cover all flue conditions.
Refit the cap after the test.
Disconnect the electrical supply at the mains and turn off the
21
13
Fig. 44. Inner case components
12
11
1
10
15
2
14
9
3
8
4
7
5
6
1. Flue hood
9. Inner case
2. Primary sensor
10. Fan assembly
3. Heat exchanger
11. Inner case cover fixing (top)
4. Combustion chamber assembly
12. Air pressure switch
5. Spark electrode assembly
6. Inner case cover fixing (bottom)
13. Combustion sensing point
7. Burner assembly
15. Main wiring harness
14. Fan harness
8. Combustion chamber fixing screw
22
Inner Case Cover Unscrew the four screws and remove. Refer to Fig 42.
Combustion Chamber Unscrew the two screws at the top and
the two wing nut extended screws at the sides, pull
forward and remove. Refer to Fig 44.
Fan
Carefully pull off the electrical connections and the
tubes from the airflow-sensing device. Unscrew the four
screws and remove the fan assembly. Refer to Fig 45.
Flue Hood Remove the fan. Unscrew the four screws and slide
out the hood. Refer to Fig 47.
Burner
Remove the combustion chamber. Carefully pull-off
the connections to the spark electrodes. Pull off the
connection to the flame sense electrode. Unscrew
the support bracket. Release the union nut beneath
the burner and carefully remove the burner. Refer to
Fig 46.
14.4 Component Cleaning
Only use a non-metallic brush to clean components. Do not use a
metal probe to clean the injectors.
Clean the fan taking care not to block air flow detector.
Clean the burner to ensure that the blades and injectors are clear.
Clean the electrodes, replace if there is any sign of deterioration.
Clean the heat exchanger. Cover the gas inlet tube and remove
any deposits from the heat exchanger from the top and bottom.
Carefully straighten any distorted fins on the heat exchanger.
Check the combustion chamber insulation and replace if there is
any sign of damage or deterioration. Refer to Section 15.5.
Clean the controls in-situ using a non-metallic brush.
Carefully refit any components removed in the reverse order.
Check that all screws are tight and the connections properly
remade with the appropriate gaskets/O-rings.
Re-commission, as necessary, for correct operation to the users
requirements. Refer to Section 12 Commissioning.
Fig. 47. Flue hood
Fig. 45. Fan assembly
1
2
1
4
2
5
3
3
1. Fan assembly
2. Fan assembly fixing screws (4)
3. Flue hood
4. Flue hood fixing screws (4)
5. Air flow detector
1. Flue hood fixing screws (4)
2. Flue hood
3. Flue hood/Heat exchanger guide
Fig. 46. Burner assembly
4
2
5
3
1
1. Burner assembly
2. Spark electrode assembly
3. Spark electrode assembly fixing screw
4. Flame sense elctrode
5. Flame sense elctrode fixing screw
23
15.1 Gas Valve
Unscrew the union connections above and below the gas valve
and remove the assembly. Disconnect/unplug the electrical
connections from the valve.
Use new gaskets when replacing the valve. Refer to Fig 48.
Set the Gas Valve:
Connect a pressure gauge to the burner and inlet pressure test
points on the valve. Refer to Fig 39.
Switch on the gas and electricity supplies.
Check for gas tightness at the gas valve inlet.
Refer to Section 12.5 Commissioning for the method of
checking/setting the pressures.
Check for gas soundness at the gas valve outlet.
Adjust the maximum and start pressure [minimum], as
necessary, to obtain the required pressures. Switch off the
appliance and disconnect the pressure gauge. and tighten the
screw. Refer to Section 12.5 and Fig 39 for setting instructions.
Check for gas soundness at the test point.
15. Replacement Of Parts
IMPORTANT: Turn off the gas supply and electrically isolate
the appliance before replacing any components.
After the replacement of any components always check for gas
soundness where relevant and carry out functional checks as
described in Section 12-Commissioning.
Any O-ring or gasket that appears damaged must be replaced.
Complete gasket and O-ring packs are available for gas and
water connections on the appliance.
Component Access
Refer to Section 14, Inspection and Servicing for access to
components.
Draining the Appliance
Primary System: Turn off the heating flow and return valves at
the appliance. Refer to Fig 17.
Open the drain tap a short tube is already connected to the drain
point. Refer to Fig. 20. Close the drain tap when the flow from the
appliance has stopped.
Fig. 48 . Lower casing - gas and water
controls.
1
1. Gas valve
2. Pump
3. Pressure guage
9
4. Relief valve
2
3
4
8
5. Manifold assembly
6. Control panel in lowered position
7. DHW sensor
8. DHW flow turbine
9. Control panel top support
10. Drain tap
7
11. Drain tube
10
11
5
6
Fig. 49. Spark electrode assembly
3
1
DHW Circuit: Turn off the mains cold water supply at the
appliance. Refer to Fig 16. Open a hot tap below the level of the
appliance to drain the domestic hot water from the appliance.
Important: A small quantity of water will remain in some
components even after the appliance has been drained.
Protect any electrical components when removing items from
the water circuits.
Component Replacement
Refer to Fig 42 and 44 for an indication of the location of the
various components.
Replace any components removed from the appliance in the
reverse order using new gaskets/O-rings/sealant/heat transfer
paste where necessary. Always check that any electrical
connections are correctly made and that all screws are tight.
Remove casing and cover panels and lower the facia onto lower
lugs, as necessary, to gain access to the components. Refer to
Section 14, Inspection and Servicing.
2
1. Spark electrode assembly
2. Fixing screw
3. Burner blade assembly (LH)
24
15.2 Spark Electrode
Remove the inner casing cover and the combustion chamber.
Carefully pull off the lead from the electrode. Unscrew the screw
and remove the assembly. Refer to Fig 49.
Ensure that the electrode is at the correct height above the
burner blade. 6.5mm ±1mm.
Fig. 50. Flame sense electrode
3
1
15.3 Flame Sense Electrode
Remove the inner casing cover and the combustion chamber.
Remove burner as in 15.4.
Carefully pull off the leads from the electrode assembly. Unscrew
the screw and remove the assembly. Refer to Fig 50.
Ensure that the sense electrode is at the correct height above
burner blade. 6.5mm ±1mm.
2
15.4 Burner
Remove the inner casing cover and the combustion chamber.
Remove the spark electrode connections. Unscrew the two
burner bracket fixing screws. Release the union connection
beneath the burner and remove the burner from the appliance.
Refer to Fig. 46. and 51. Do not omit the gasket when fitting the
new burner.
1. Flame sense electrode
2. Fixing screw
3. Burner blade assembly (RH)
Fig. 51. Burner
2
1
5
3
4
5
8
6
9
10
10
12
7
1.
2.
3.
4.
5.
6.
7.
Flame sense elctrode
Spark electrode assembly
Burner blade assembly (LH)
Burner manifold
Burner blade assembly location points
Burner blade assembly (RH)
Cross- lighting strip fixing screws (2)
8.
9.
10.
11.
12.
13.
Cross-lighting strip
Cross-lighting strip fixing holes (2)
Burner assembly
Burner support bracket
Burner fixing screw
Bracket fixing screws (2)
25
11
13
15.5 Combustion Chamber Insulation, Front &Sides
Remove inner casing door and combustion chamber.
Remove damaged insulation, replacement is the reverse of
removal. See Fig 52.
Combustion Chamber Insulation, Rear
Remove heat exchanger as described in 15.21.
Remove side panels first.
Pull insulation forward and up to remove.
Replacement is the reverse of removal. Refer to Fig 52.
Fig. 54. Relief valve boiler drain connection
1
2
3
Fig. 52. Combustion Chamber Insulation
Front and Sides.
2
6
5
4
3
1. Pump
2. Boiler drain
3. Pressure gauge capillary
4. Boiler Drain ON/OFF
5. Relief valve
6. Relief valve drain connection (push fit)
1
15.7 Relief Valve
Remove the clip-on facia cover, cabinet and lower the facia onto
the lower support lugs.
Check that the appliance has been fully drained.
Unclip and pull-out the valve body. Refer to Fig 54
1. Insulation panel-side
2. Insulation panel-front
Fig. 55. Water flow turbine.
3. Combustion chamber assembly
4
15.6 Pressure Gauge
Remove the clip-on facia cover, cabinet and lower the facia panel
onto the lower support lugs. Refer to Fig 43. Check that the
appliance has been fully drained. Withdraw the clip and remove
the pressure-sensing head. Refer to Fig 53.
Unclip the gauge head from its mounting bracket and remove.
Refer to Fig 53.
Do not omit the washer from the pressure capillary when fitting
the replacement gauge.
2
1
Fig. 53. Pressure Gauge head
2
1. Flow turbine
2. Flow turbine clips
3. Inlet
3. Outlet
1
4
2
3
3
15.8 Flow Turbine
Drain the DHW circuit as described at the start of Section 15
preceding.
Remove the clip on facia cover, cabinet and lower the facia panel
onto the lower support lugs. Separate the in-line connector. Remove
the two fixing clips and withdraw the turbine. Refer to Fig 48 and 55.
Do not omit the gaskets when fitting the replacement turbine.
1. Pump
2. Pressure gauge capillary
3. Pressure gauge head
4. Mounting bracket
26
15.9 Inlet Water Filter
Remove the flow turbine as described in 15.8 preceding.
Taking care, remove flow restrictor assembly from the flow turbine
inlet. Refer to Fig 55 Carefully clean wire mesh by back flushing
with water or replace assembly if necessary. Refer to Fig 56.
15.12 Clock/Programmer
Remove the facia by gently pulling it away from the boiler to
release the clips.
Remove the clock/programmer assembly by releasing the clip at
the top of the clock/programmer and ease away from the
control panel being careful not to pull on the connector lead.
Unplug the connector at the control board. Refer to Fig 58.
Comprehensive instructions are sent with the new control.
Fig. 56.Inlet water filter and flow restrictor
1. Flow restrictor
1
2. Inlet water filter
Fig. 58. Programmer connection
2
7
6
15.10 Control Board
Remove the clip-on facia cover, cabinet and the connections
cover. Carefully disconnect all the electrical connections. Refer to
Fig 35 and 43.
Remove the facia panel and unscrew the four screws and remove
the cover from the rear of the facia. Refer to Fig 57. Lift out the
control board. Refer to Fig 57
Pull out and transfer the transformer to the new board.
Re-commission the appliance to check and set the burner
pressures. Refer to Section 12, Commissioning.
4
5
3
2
15.11 Transformer
Unscrew the four screws and remove the cover from the rear of
the facia as described in 15.10 preceding. Refer to Fig 57.
Pull out and transfer the transformer to the new board. Refer to
Fig 57.
1
Fig. 57. Control board
3
1. Facia (gently pull forward to un-clip and remove)
2. Control panel (boiler outer casing in place)
3. Programmer cover (un-clip to remove. See Fig. 34)
4. Programmer location in detail
4
5. Programmer connections (See Fig. 34)
6. Programmer connector plug
2
7. Programmer
5
15.13 Fan
Remove the inner casing cover.
Remove the fan as described in Section 14.3, Inspection and
Servicing.
Ensure that all the connections are correctly made to the new
fan.
1
1. Control panel
2. Rear cover
3. Rear cover fixing screws (4)
15.14 Air Flow Detector
Remove the fan as described in 15.13 preceding.
Unscrew and withdraw, through the fan outlet, the airflow
detector. Refer to Fig 45.
4. Transformer
5. Control board
27
15.15 Primary [ch] Sensor
Remove the clip-on facia cover, cabinet and inner casing cover.
Carefully pull-off the connections. Release the clip and lift out the
sensor. Refer to Fig 59 and 62.
Do not omit the heat transfer paste when fitting the replacement
sensor.
Fig. 59. Primary (CH) sensor.
15.16 Overheat Thermostat
Remove the clip-on facia cover, cabinet and the inner casing
cover.
For the position of the overheat thermostat refer to Fig 62.
Carefully pull-off the connections. Unscrew the two screws and
remove the thermostat and fixing bracket. Refer to Fig 60. Apply
a small quantity of heat transfer paste to the face of the
replacement thermostat.
Carefully position the thermostat so that the connections are
away from the flue hood.
1
2
15.17 DHW Sensor
Remove the clip-on facia cover, cabinet and lower the facia onto
the lower support lugs.
Carefully pull off the connections. Unscrew the clip and remove
the sensor.
Apply a small quantity of heat transfer paste to the face of the
replacement sensor. Refer to Fig 61.
1. CH Sensor
2. Clip
Fig. 60. Overheat thermostat
15.18 Pump
Check that the primary circuit has been fully drained.
Use a 4mm Allen key to release the four pump head fixing
screws and remove the pump head. Refer to Fig 48.
Disconnect and transfer the electrical connections to the new
pump head. Take care not to scratch the mating surfaces.
1
15.19 Expansion Vessel
It will be necessary to remove the appliance from the wall to
replace the expansion vessel. Refer to Fig 37.
Alternatively the specified replacement can be fitted into the
heating system return as close to the appliance as possible.
Re-fill and pressurise the system as described in Section 13
Commissioning.
3
2
15.20 Auto Air Vent
Drain the primary circuit.
Unscrew and remove the auto air vent. Do not omit the sealing
washer when fitting the replacement air vent. Remove the cap.
Refer to Fig 37.
1. Overheat thermostat
2. Fixing bracket
3. Overheat thermostat fixing screw
15.21 Primary Heat Exchanger
Check that the appliance has been fully drained.
Remove the temperature sensors as described in 15.15, 16 and
17 preceding.
Remove the combustion chamber, fan and flue hood as
described in Section 14.3, Inspection and Servicing and burner
as described in 15.4. NOTE: The heat exchanger is unsupported
when both the combustion chamber and flue hood are removed.
Undo the four union connections and remove the heat exchanger.
Do not omit the sealing washers when fitting the replacement
heat exchanger. Refer to Fig 62.
Fig. 61. DHW sensor
3
2
1
1. DHW sensor
2. DHW sensor fixing bracket and screw
3. DHW outlet pipe
28
Fig. 62. Primary heat exchanger
1
5
6
3
2
1. Heat exchanger
2. CH flow/return pipes
3. DHW inlet/outlet pipes
4. Seal
4
5. Overheat thermostat
6. Primary sensor
15.22 Air pressure Switch
The air pressure switch is held in position by a fixing bracket. In
order to remove the switch:
Gently move outwards the securing clips holding the switch to
the bracket.
Remove the air pressure tubes and wires from the switch.
Push the replacement switch, with the tube connectors pointing
forwards, into the bracket and then replace the wires and pressure tubes.
If the fixing bracket needs replacing, remove the switch as
described above then remove the two screws holding the bracket
to the top of the appliance. Refer to Fig 63 and 64.
Fig. 64. Air flow pressure switch
5
3
4
15.23 Sight Glass
Remove and replace the inner casing cover complete.
Refer to Section 14.3, Inspection and Servicing. Refer to Fig 42.
+Ve
2
—Ve
Fig. 63. Air flow pressure switch location
2
1
3
6
1
4
5
1. Electrical connections
2. Air pressure switch
6
3. Screws
4. Air pressure switch fixing clip
5. Securing clip
6. Tube connectors
1. Air pressure switch
2. Fixing bracket
3. Air pressure switch
fixing clip
4. Combustion sensing
point location
5. Negative pressure tube (–)
6. Positive pressure tube (+)
29
16. Short Parts List
Key
No.
G.C. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
E88-141
E88-142
E88-143
E88-144
E88:450
E88:451
E88-146
E88-169
E88-170
375-696
E88-171
378-809
299-363
E88-172
E88-173
E88-174
E88-175
E88-176
E27-580
E88-177
E27-587
H02-152
E88-179
E88-180
E88-181
E88-182
E88-183
E88-184
E88-185
H02-155
H02-157
Part
Burner 24Si II NG RSF
Burner 24Si II LPG RSF
Burner 28Si II NG RSF
Burner 28Si II LPG RSF
Gas Valve NG Dungs BN771SL040 - 239675
Gas Valve LPG Dungs BN771SL040 - 239676
Air Pressure Switch
E lectrode Set (Flame and Ignition)
Overheat Stat
NTC/Thermistor DHW
NTC/Thermistor CH
Air Vent Manual 1/4 BSP
Air Flow Sensor
Heat Exchanger 24Si II
Heat Exchanger 28Si II
Insulation Pack 24Si II
Insulation Pack 28Si II
Pressure Gauge
Pressure Relief Valve
Pump
Expansion Vessel
Control Board
Fan Assembly - 24Si II
Fan Assembly - 28Si II
Flow Sensor
Seal-Door Extrusion
Transformer
Flow Regulator 24Si II
Flow Regulator 28Si II
Code Plug 24Si II RSF
Code Plug 28Si II RSF
Qty
WHS
Part No.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
8 716 101 900 0
8 716 102 396 0
8 716 105 008 0
8 716 105 009 0
8 716 102 673 0
8 716 102 868 0
8 716 104 896 0
8 716 101 901 0
8 717 206 200 0
8 716 142 302 0
8 714 500 029 0
8 716 140 516 0
8 716 141 000 0
8 715 406 670 0
8 715 406 814 0
8 716 101 877 0
8 761 105 010 0
8 716 142 398 0
8 716 156 764 0
8 716 143 116 0
8 715 407 154 0
8 748 300 488 0
8 716 104 814 0
8 716 104 815 0
8 716 146 164 0
8 716 104 609 0
8 747 210 294 0
8 716 141 255 0
8 716 141 253 0
8 714 421 166 0
8 714 421 167 0
1
1
1
1
1
1
1
2
1
1
1
1
7 716 192 281
7 716 192 282
7 716 192 288
7 716 192 289
7 716 191 068
7 716 191 079
7 716 191 013
7 716 191 014
7 716 191 016
7 716 192 246
7 716 192 027
7 716 192 028
Accessories and Kits
A001
A002
A004
A005
A006
A007
A008
A009
A010
A011
A012
A013
Charging Link Assembly
Installer Pre-Filling Kit
Gas Conversion Kit NG to LPG 24Si II
Gas Conversion Kit NG to LPG 28Si II
Simplefit Telescopic Flue Kit - F105H500
Vertical Flue Kit
90° Flue Elbow - F106E90
45° Flue Elbow (Pair) - F 106E45
Vertical Flue Adaptor Kit
Security Kit
Mechanical Programmer
Digital Programmer
30
7
12
9
1-4
8
5/6
10
13
8
11
16 -17
18
14 -15
19
22
20
21
25
23 - 24
28 - 29
27
26
31
30 - 31
17. Operational Flow Diagrams
CENTRAL HEATING FUNCTION
MAIN SWITCH
ON
CENTRAL
HEATING
DEMAND
Pump on.
Fan ON/
ignition
sequence.
Burner Light
On.
Three minute
wait
Fifteen second
minimum
burner
pressure then
ramp up
pressure over
next one
minute
Room
thermostat
and/or mains
programmer
(or link) On
AND
facia
programmer
(if fitted) On
AND
CH control
knob On
Modulate gas
to maintain
flow
temperature
set by control
knob
(50-82°C)
DEMAND
END
Overrun
function
(see overleaf)
Over temperature shutdown if flow
temperature
5°C above set
value
Gas valve Off.
Burner light
off. (Pump still
On)
DOMESTIC HOT WATER FUNCTION
Flow sensor
signal
(Tap open)
MAIN SWITCH
ON
DOMESTIC
HOT WATER
DEMAND
(Priority over
CH demand)
YES
Is CH
interrupted?
Pump continue
4 seconds if
primary temp
above DHW
setting. Burner
to MAX.
Modulate gas
to maintain
delivered
water
temperature
set by control
knob
(40-60°C)
NO
Ignition
sequence and
burner to MAX
DHW temp
drops to user
set point
Gas valve off.
Primary
78°C
Gas valve off.
Pump on
Over
temperature
shut-down if
water
temperature
above 80°C
Primary
temperature
94°C
32
DEMAND
END
Overrun
function
(see overleaf)
OVERRUN FUNCTION
END DHW
DEMAND
Pump overrun
function active
for 3 minutes
Fan low speed
35 seconds
END CH
DEMAND
Pump on if
primary temp
above 80°
until temp
below 75°C
Fan low speed if
primary temp
above 80°C until
below 75°C.
Pump runs
for
3 minutes
AUTOFROSTAT FUNCTION
No demand
and primary
temperature
below 8°C
Internal
"Autofrostat"
demand
Run pump
Monitor
central
heating
sensor
Below
5°C
5°C
to
9°C
Above
9°C
Commence normal
central heating mode
until temperature
reaches 20°C
33
Return to
normal off
state
18. Fault Finding
Note: This fault-finding information is for guidance only. Worcester, Bosch Group cannot be held responsible for costs incurred by persons
not deemed to be competent.
By flashing at various rates, the oval shaped facia light will indicate specific fault conditions. If this is used with other observations during
a fault, then every normal fault can be identified.
To use the fault finding system, use the table below to select the failure condition during your fault. The most common causes are listed,
then refer to the test in the following section. This fault finding system assumes that the appliance has been operating normally until the
time of failure (ie not a first installation fault).
PRELIMINARY CHECKS
Preliminary electrical system checks are the first electrical checks to be carried out during a fault-finding procedure. On completion of
the Service/Fault-Finding task which has required the breaking and remaking of electrical connections, check (a) EARTH CONTINUITY,
(b) SHORT CIRCUIT CHECK, (c) POLARITY and (d) RESISTANCE TO EARTH.
FAULT LIST
OBSERVED FAULT
COMMON CAUSES
SEE TEST
No lights and no functions
(with demand)
No mains Voltage supply.
Fuse F1 or F2 blown.
Transformer or connector failed.
Board fault.
A
No CH function (DHW OK)
No link at ST2 Ls to Lr, or failed external control
input to Lr.
Failed programmer.
Board fault.
B
No DHW function (CH OK)
Flow sensor failure.
DHW sensor (LED 4 flash/second).
Board fault.
C
Flash once per second
No gas or low gas pressure.
Weak spark or spark not across elecrodes.
Gas valve leaking or failed.
Low water pressure or boiler dry.
Pump fail.
Primary sensor position.
Flame sensor fail or connector.
Overheat stat tripped or disconnected or faulty.
Blocked burner.
Blocked heat exchanger.
Faulty harness.
Board fault.
D
Ignition lockout
Overheat lockout
Internal error
(reset lockout by gently
pressing reset button
for 5 seconds)
Flash 4 times per second
Code plug missing or failed.
CH or DHW Sensor fault or out of position.
Air pressure switch fault or condense in tubes.
Fan fail or stiff.
Blocked flue.
Faulty harness.
Board fault.
E
Flash 8 times per second
GV mode switch
Gas Valve mode switch on min or max.
F
Burner on with no demand
Autofroststat.
Board fault.
Water temperature too hot
Sensor off pipe.
G
H
Water temperature too cool
Low gas pressure.
Pot P1 not turned up.
Stiff/sticking gas valve.
Stiff/sticking flow sensor.
Board fault.
34
I
NOTE: It is normal for
there to be no facia
lights if the boiler is in
normal overtemperature condition.
Continue this test if
this fault occurs when
the appliance is cold.
Is there a 230V AC live
supply across
Terminal ST2 pins L
and N?
No
Check electrical
supply to boiler.
TEST A
Yes
Switch off electrical
power.
Has fuse F1 blown?
No
Has fuse F2 blown?
No
Yes
Yes
Yes
Likely to be caused by
control board internal
fault or low voltage
wiring (eg shorts to
chassis). Replace fuse
F2 and check wiring
or replace control
board.
Caused by mains 230V
parts external to the
control board ie (wiring
to or faults within)
pump, fan, transformer
or other external
controls connected to
ST2. Check all these
parts for malfunction.
Repair/replace part,
replace fuse and run
boiler.
Note: tracks on board
may also be damaged.
Replace board if
necessary
Replace transformer.
NOTE: Lights will be
off and pump will run
if boiler is in 3min
anticycle condition.
With CH control knob
fully clockwise, if
there is still no CH
function, continue:
TEST B
Is there a 230V AC live
supply across
Terminal ST2 pins Lr
and N?
No
There is no heat
demand. Check room
thermostat or external
programmer (or link).
Yes
Is there a facia
mounted programmer
at connection ST5 at
right-hand end of
board?
No
Replace
control
board.
Yes
Remove programmer
connector from edge
of board. Does the
boiler now ignite?
Remove control board from facia
and separate transformer from
board. Measure resistance across
the two pairs of adjacent pins on
the transformer. Is any coil above
120 ohms?
No
Yes
Correctly set or
replace programmer.
35
No
Replace
control
board.
Disconnect the 3 way
in-line connector to
the turbine.
Is there 5VDC between
the two outer pins
(main harness side)?
Take care not to
damage the pins.
No
TEST C
No
Yes
Yes
Re-connect the 3-way
connector and open a
tap to run the turbine.
Is there between 1.5
and 4.5VDC across
the green and black
wires/terminals?
Is there continuity in
the main harness?
Replace control
board.
Yes
No
Replace turbine.
36
Replace main
harness.
Is the gas supply
connected and at the
correct pressure?
No
Rectify gas supply
problem.
Yes
Remove front panel.
Reset and restart the
boiler. Can a flame be
seen through the spy
glass?
No
Remove inner cover.
Reset and restart the
boiler. Does a spark
occur across the
electrodes?
No
Are the electrodes and
gap and connections
in good order?
No
Repair or replace
spark electrode
or HT leads
Yes
Test resistance of each
ignition cable.
Is it 2000-3000 ohms?
Yes
No
Replace (both) ignition
cables
Yes
Replace
control board.
Turn off boiler. Remove
the multiway
connector from board
position ST16.
Test resistance across
connector contact
pins 1 and 2
(green wires)
and 8 and 9
(brown wires).
Are both reading
below 100 ohms?
Yes
No
Remove both
connectors from gas
valve.
Is there continuity
from these
to multiway
connector?
Yes
TEST D
Replace gas valve.
Yes
Is there continuity
between pins 6 and 7?
(green wires to HL
stat)
No
Yes
Replace control board.
If problem not solved
replace gas valve.
Is the boiler fully
water pressurised and
is all air vented?
No
Rectify fault.
Yes
Reset and restart the
boiler in CH mode.
Does the pump run?
No
Replace or repair
pump.
Yes
37
Replace overheat stat
or wiring to it.
No
Repair or replace
harness.
Yes
Turn off boiler. Remove
inner casing cover and
inspect the primary
sensor (on heat
exchanger in front of
overheat thermostat).
Is it correctly fixed to
pipe?
No
Re-fix sensor to pipe.
Yes
Remove combustion
chamber cover.
Is the sense electrode
and lead in good
condition and is gap
correct?
No
Replace flame sensor
or wiring.
Yes
Remove multiway
connector from board
position ST16.
Is there continuity
from pin 10 (green
wire) to flame sensor?
No
Yes
Does the flashing fault
signal occur at the
start of a demand?
No
If flashing occurs at
the end of a demand.
Gas valve leak is
detected.
Replace gas valve.
If flashing occurs during a
demand.
Pump could be partially
blocked.
Clean pump & flush system.
Yes
Relace control board.
NOTE: It is not
possible to reliably
check the cross-light
performance of the
burner, or the
efficiency of the
gas/water heat
exchanger.
If there is still a
problem, investigate
flue problems or
replace burner or
injector or heat
exchanger.
38
Is the Code plug fitted
and
fully home?
No
Fit/push fully home
Yes
Is the multiway
connector at board
position ST16 pushed
fully home on to the
board?
No
Push fully home
Yes
Check the DHW
sensor. Is it correctly
fitted onto the pipe
with heat conductive
paste between the
pipe and sensor?
No
Re-fix sensor onto pipe
Yes
Remove multiway
connector from board
position ST16. Test
resistance across
contacts 15 and 16
(black & yellow wires).
Is it between 1 kOhm
and 30 kOhm?
No
Is there continuity
from individual
contacts 15 and 16 to
DHW sensor?
No
Repair or replace
harness.
Yes
TEST E
Check or replace
DHW sensor.
Yes
Test resistance across
contacts 12 and 13
( red & black wires). Is
it between 1 kOhm
and 30 kOhm?
No
Is there continuity
from individual
contacts 12 and 13 to
CH sensor?
No
Yes
Check or replace
CH sensor.
Yes
Test resistance across
contacts 13 and 14
(black & blue wires).
Is it open circuit?
No
Air pressure switch
is shorting.
Check tubes for
blockage or replace
switch.
Yes
Turn off electrical
supply.
Remove fan connector
from board position
ST1.
Test resistance across
contacts to black &
white cables.
Is it between 75 and
175 ohms?
No
Yes
Test resistance across
contacts to black &
red cables. Is it
between 20 and 60
ohms?
Check/repair fan
harness or repalce fan.
No
Yes
39
Repair or replace
harness.
Yes
Replace multiway
connector to position
ST16 (but not fan
connector at ST1) and
reset/restart the
boiler.
Is there mains 230V
across the right (L)
and left (N) tracks at
board position ST1?
NOTE: Take care not to
short L to N.
No
Replace control board.
In the unlikely event
of this not solving the
problem replace code
plug.
Yes
Replace fan connector
ST1.
Remove electrical
connectors from air
pressure switch and
reset/restart boiler.
Is there continuity
between C and NO
terminals (where wires
were fitted) when the
fan runs?
(Test within 30
seconds).
No
Pressure switch has
not closed. Are the
silicon tubes in good
condition and free of
condensation.
No
Replace tubes. If
condensation has
occurred, also replace
pressure switch and
check condition of
Venturi in the fan.
Yes
Inspect the flue. Is it
free of any
restrictions?
No
Rectify flue problem.
Yes
Replace air pressure
switch.
Note: In the unlikely
event of this not
solving the problem
inspect the pressure
pick-up (Venturi) in the
fan or fan may not be
running freely.
Yes
Does the burner ignite
(burner light on) and
run for a short priod
before the fault
occurs?
No
Remove multiway
connector from board
position ST16.
Is there continuity of
black & blue cables to
the air pressure
switch?
No
Yes
Yes
Replace control board.
TEST F
Pressure switch has
opened during
operation.
Check flue for
blockage.
Also investigate sense
tubes and pressure
switch.
The gas valve mode
switch (concealed by
the facia side panel)
is not set correctly
Turn to 'NORM'
position
40
Repair cables or
replace main harness.
TEST G
Is the boiler in a very
cold environment (less
than 5°C)?
No
Replace control board.
Note: A damp board
could cause this fault.
Yes
TEST H
Boiler is running in
“Autofrost stat” mode.
See Section 17.
Hot water
temperature always
too hot during a
demand (not
regulating).
Hot water sensor
could be off or poorly
fixed to pipe.
Repair or replace.
Water flow
temperature very low
(with all knobs set at
maximum).
Does the problem
occur in CH mode
only?
Could be
domestic hot
and cold pipes
crossed.
No
Yes
TEST I
Increase
potentiometer to
allow more gas in CH
mode.
Remove multiway
connector from board
position ST16. Is the
resistance across
contacts 4 and 5 (blue
wires) below 60
ohms?
No
Replace gas valve or
check wiring.
Yes
No
No
Is the CH limit
potentiometer
(concealed behind
facia bottom panel)
set to maximum?
Check flow sensor:
with boiler cool,
slowly open a HW tap.
Does the boiler ignite
with a flow of about
3 l/min?
(Check using a
measuring jug and
stop watch i.e 500ml
in 10 sec.
Yes
It is not possible to
easily isolate the fault.
The most likely causes
are control board (fail),
heat exchanger
(blocked) or
gas valve (sticking).
Yes
41
Turbine sticking or
seized.
Replace the turbine.
19. Conversion Instructions
ONLY COMPONENTS SUPPLIED BY WORCESTER
SHOULD BE USED.
ONLY COMPETENT PERSONNEL SHOULD ATTEMPT
THE CONVERSION.
CONVERSION FROM NATURAL GAS TO LPG SHOULD
NOT BE CARRIED OUT ON APPLIANCES INSTALLED IN
A ROOM OR INTERNAL SPACE BELOW GROUND LEVEL
24kW
Conversion Kit NG to LPG 7 716 192 288
12. Refit the plastic sealing cap to the gas valve modulating valve
and seal with a dab of paint or similar.
13. Turn off the boiler and when cool peel off the arrow from the
data plate on the combustion box front panel and re-stick
against the gas type for which the boiler has been converted
and adjusted.
13. Replace the boiler front panel.
The conversion is now complete.
Fig 1. Gas Valve
28kW
7 716 192 289
1. Ensure the gas service cock is turned OFF and the electrical
supply is ISOLATED.
Max
2mm
Allen key
Burner
pressure
test point
2. Refer to the Installation and Service Instructions Section14:
Inspection and Servicing to remove the cabinet front panel
and outer casing.
Min
3mm
Allen key
3. Follow the dismantling instructions to remove the burner.
Refer to Section: 14.3 Inspection and Servicing.
Minimum /
Maximum
pressure
adjuster Allen key*
(see Note)
4. Remove the burner blades as shown in 15.4.
5. Replace the burner manifold with a new one supplied in the kit.
6. Refit burner blades taking care to assure that the cross
lighting strip and blades are correctly fitted and aligned.
7. Remove the gas valve and replace with the gas valve
supplied in the kit. Refer to the Installation and Servicing
Instructions Section 15- Replacement of Parts.
NOTE: Replace the fibre washer with one of those supplied
in the kit.
8. Refit the burner assembly to the gas valve using the other
fibre washer supplied in the kit.
9. Ensure that the sealing grommet around the burner
manifold is correctly sealed to the boiler casing.
9. Remove plastic anti-tamper seal and plastic cap from the gas
valve.
Main gas
valve
connections
Inlet
pressure
test point
Gas valve bracket
10. Turn on the gas and electricity supplies and follow the
commissioning procedure to confirm gas soundness and
correct boiler operation.
Ensure that the joints on the gas valve to the burner and
inlet are both checked for gas soundness.
24Si II
NOMINAL BOILER RATINGS (10 Minutes After Lighting)
BOILER ADJUSTED FOR G20 (Natural Gas)
BURNER
OUTPUT
INPUT (Net)
GAS RATE
PRESSURE
kW
kW
m bar.
m3/h
6.9
7.9
0.9
0.84
24
26.4
12.1
2..8
6.9
24
BOILER ADJUSTED FOR G31 (Propane)
7.9
3.1
0.32
26.4
35.0
1.08
*Note: Clockwise
to increase and
anti-clockwise to
decrease the pressure.
Injector sizes and markings
G20 Natural gas
G31LPG
24kW 1.07 mm
0.65 mm
(marked 107)
(marked 65)
28kW 1.12 mm
0.69 mm
(marked 113)
(marked 69)
11. Check and adjust the setting pressures to the values in
Table 1 and adjust if necessary. Refer to the Installation and
Service Instructions Section 12.5 for the setting of the gas
valve and refer to Fig 1.
Table 1.
Electrical
connections
Gas valve
modulator
(Blue:Blue) sealing
cap
Table 1.
28Si II
NOMINAL BOILER RATINGS (10 Minutes After Lighting)
BOILER ADJUSTED FOR G20 (Natural Gas)
BURNER
OUTPUT
INPUT (Net)
GAS RATE
PRESSURE
kW
kW
m bar.
m3/h
8.1
9.2
0.7
0.97
28
30.7
13.1
3.25
8.1
28
BOILER ADJUSTED FOR G31 (Propane)
9.2
2.8
30.7
34.5
0.38
1.25
Natural Gas: Net Input = Gross Input x 0.901
LPG (Propane): Net Input = Gross Input x 0.922
NOTE: With longer flue lengths, not using a restrictor, the minimum burner pressure will rise, naturally due to the flue, to 1.1mbar on G20
appliances only.
42
BENCHMARK No.
GAS BOILER COMMISSIONING CHECKLIST
COLLECTIVE MARK
BOILER SERIAL No.
CONTROLS
NOTIFICATION No.
To comply with the Building Regulations, each section must have a tick in one or other of the boxes
TIME & TEMPERATURE CONTROL TO HEATING
TIME & TEMPERATURE CONTROL TO HOT W ATER
ROOM T/STAT& PROGRAMMER/TIMER
PROGRAMMABLE ROOMSTAT
CYLINDER T/STAT& PROGRAMMER/TIMER
COMBI BOILER
HEATING ZONE VALVES
FITTED
NOT REQUIRED
HOT W ATER ZONE VALVES
FITTED
NOT REQUIRED
THERMOSTATIC RADIATOR VALVES
FITTED
AUTOMATIC BYPASS TO SYSTEM
FITTED
NOT REQUIRED
FOR ALL BOILERS CONFIRM THE FOLLOWING
THE SYSTEM HAS BEEN FLUSHED IN ACCORDANCE WITH THE BOILER MANUFACTURER S INSTRUCTIONS?
THE SYSTEM CLEANER USED
THE INHIBITOR USED
FOR THE CENTRAL HEATING MODE, MEASURE & RECORD
GAS RATE
m 3/hr
tf3/hr
BURNER OPERATING PRESSURE (IF APPLICABLE)
N/A
mbar
CENTRAL HEATING FLOW TEMPERATURE
¡C
CENTRAL HEATING RETURN TEMPERATURE
¡C
FOR COMBINATION BOILERS ONLY
HAS A W ATERSCALEREDUCERBEENFITTED?
YES
NO
WHAT TYPE OF SCALE REDUCER HAS BEEN FITTED?
FOR THE DOMESTIC HOT WATER MODE, MEASURE & RECORD
GAS RATE
m 3/hr
N/A
MAXIMUM BURNER OPERATING PRESSURE (IF APPLICABLE)
tf3/hr
mbar
COLD WATER INLET TEMPERATURE
¡C
HOT W ATER OUTLET TEMPERATURE
¡C
W ATER FLOW RATE
lts/min
FOR CONDENSING BOILERS ONLY CONFIRM THE FOLLOWING
THE CONDENSATE DRAIN HAS BEEN INSTALLED IN ACCORDANCE WITH
THE MANUFACTURER S INSTRUCTIONS?
YES
FOR ALL INSTALLATIONS CONFIRM THE FOLLOWING
THE HEATING AND HOT W ATER SYSTEM COMPLIES
WITH CURRENT BUILDING REGULATIONS
THE APPLIANCE AND ASSOCIATED EQUIPMENT HAS BEEN INSTALLED AND COMMISSIONED
IN ACCORDANCE WITH THE MANUFACTURER S INSTRUCTIONS
IF REQUIRED BY THE MANUFACTURER, HAVE YOU RECORDED A CO/CO2 RATIO READING?
N/A
THE OPERATION OF THE APPLIANCE AND SYSTEM
CONTROLS HAVE BEEN DEMONSTRATED TO THE CUSTOMER
THE MANUFACTURER S LITERATURE HAS BEEN LEFT WITH THE CUSTOMER
COMMISSIONING ENG S NAME
PRINT
CORGI ID No.
SIGN
DATE
YES
CO/CO2 RATIO
SERVICE INTERVAL RECORD
It is recommended that your heating system is serviced regularly
and that you complete the appropriate Service Interval Record Below.
Service Provider. Before completing the appropriate Service Interval Record below, please ensure you have carried out the service
as described in the boiler manufacturer s instructions. Always use the manufacturer s specified spare part when replacing all controls
SERVICE 1 DATE
SERVICE 2 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
SIGNATURE
SIGNATURE
SERVICE 3 DATE
SERVICE 4 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
ENGINEER NAME
COMMENTS
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 5 DATE
SERVICE 6 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 7 DATE
SERVICE 8 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 9 DATE
SERVICE 10 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
This manual is to be used in conjunction
with the variant part number of the bar
code below:
www.worcester-bosch.co.uk
Bosch Group
Worcester, Bosch Group, Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: 01905 754624. Fax: 01905 753130.
Technical Helpline 08705 266241.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Limited.
This booklet is accurate at the date of printing but will be superseded and should be disregarded if specifications and/or appearances are changed in the interests
of continued improvement.
All goods sold are subject to our official Conditions of Sale, a copy of which may be obtained on application.
PUBLICATION 8 716 114 750a (11/07)